Private Ethereum blockchain: missing trie node

Question

I deployed a private blockchain with the following steps:

1. Setting the difficulty to a fixed value (see Running a “quick” Ethereum private network for experimentation and testing) and creating the genesis.json
   
2. Creating the genesis block
   geth --datadir ~/.geth init ~/.geth/genesis.json
   
3. Script miningontransaction.js for mining only when there are pending transactions (see Mining until x confirmations have been achieved):

   miner.setEtherbase("0xac2c266b110979b162fbcbe994da5b1121b3e2ee");
   var minimum_confirmations = 12;
   var mining_threads = 1
   var txBlock = 0
   function checkWork() {
       if (eth.getBlock("pending").transactions.length > 0) {
           txBlock = eth.getBlock("pending").number
           if (eth.mining) return;
           console.log("Transactions pending. Mining...");
           miner.start(mining_threads)
           while (eth.getBlock("latest").number < txBlock + 12) {
               if (eth.getBlock("pending").transactions.length > 0) txBlock = eth.getBlock("pending").number;
           }
           console.log("12 confirmations achieved; mining stopped.");
           miner.stop()
       }
       else {
           miner.stop()
       }
   }
   eth.filter("latest", function(err, block) { checkWork(); });
   eth.filter("pending", function(err, block) { checkWork(); });
   checkWork();
   

4. Starting one node

   geth \
       --verbosity 3 \
       --datadir $HOME/.geth \
       --nodiscover \
       --syncmode "full" \
       --gcmode "archive" \
       --cache 2659 \
       --port 30300 \
       --ws \
       --wsaddr "0.0.0.0" \
       --wsport 8006 \
       --wsapi "personal,db,eth,net,web3,txpool,miner" \
       --wsorigins "*" \
       --rpc \
       --rpcaddr "0.0.0.0" \
       --rpcport 8005 \
       --rpcapi "personal,db,eth,net,web3,txpool,miner" \
       --rpcvhosts "*" \
       --rpccorsdomain "*" \
       --networkid 14562 \
       --preload "$HOME/miningontransaction.js" \
       console
   

   
   

Sometimes (completely irregularly) the node stops with the following on the console:

ERROR[08-13|01:20:01.160] Failed to reset txpool state             err="missing trie node 0ebb4a8b33e7945d2bfdf2b5e7c487bdd302e4b40a010389606657cca6132301 (path )"
ERROR[08-13|01:20:03.161] Failed to create mining context          err="missing trie node 0ebb4a8b33e7945d2bfdf2b5e7c487bdd302e4b40a010389606657cca6132301 (path )"

After restarting the node (step 4), the node runs perfectly again. What am I missing?